Boat hulls have historically been made of many different types of material such as aluminum, steel or wood. Another common material used in the manufacture of boat hulls is a laminate material made of fiberglass-reinforced resin.
Open face molds are frequently used to manufacture fiberglass hulls. To make a hull with an open face mold, a layer of gel coat is frequently first applied to the mold. Next, a barrier layer is often applied to the gel coat. Finally a layer of fiberglass-reinforced resin is applied to the barrier layer. When the hull is removed from the mold, the gel coat provides a smooth, aesthetically pleasing outer surface of the hull. The barrier layer prevents the fiberglass from printing or pressing through the gel coat. The fiberglass provides the hull with structural rigidity.
With fiberglass boats, it is often desirable to inject foam into foam compartments formed within the boats. The injection of foam presents several problems. For example, when foam is injected into a boat, pressure generated by the foam injection process can cause portions of the boat to bow or buckle outward thereby negatively affecting the appearance and structural integrity of the boat. This can be particularly problematic with respect to unsupported parts manufactured by injection molding or resin transfer molding operations. Also, to access foam chambers within a boat, it is often necessary to drill holes through portions of the boat. This is problematic because the drilling of holes can cause the aesthetically pleasing outer gel coat surface to be damaged. The repair of such damage can be time consuming.